Tunable features of magnetoelectric transformers

We have found that magnetostrictive FeBSiC alloy ribbons laminated with piezoelectric Pb(Zr,Ti)O
₃
fiber can act as a tunable transformer when driven under resonant conditions. These composites were also found to exhibit the strongest resonant magnetoelectric voltage coefficient of 750 V/ cm-Oe. The tunable features were achieved by applying small dc magnetic biases of -5 ⩽ H
_dc
⩽ 5 Oe. The features include 1) a high voltage gain of -55 ⩽ V
_gain
⩽ 55; and 2) a large current-to-voltage conversion of -2000 ⩽αI-V ⩽ 2000 (V/A). The tunable transformer features can be attributed to large changes in the piezomagnetic coefficient and permeability of the magnetostrictive phase under H
_dc.